@article{ZehbeZehbe2016, author = {Zehbe, Rolf and Zehbe, Kerstin}, title = {Strontium doped poly-epsilon-caprolactone composite scaffolds made by reactive foaming}, series = {The European journal of the history of economic thought}, volume = {67}, journal = {The European journal of the history of economic thought}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0928-4931}, doi = {10.1016/j.msec.2016.05.045}, pages = {259 -- 266}, year = {2016}, abstract = {In the reconstruction and regeneration of bone tissue, a primary goal is to initiate bone growth and to stabilize the surrounding bone. In this regard, a potentially useful component in biomaterials for bone tissue engineering is strontium, which acts as cationic active agent, triggering certain intracellular pathways and acting as so called dual action bone agent which inhibits bone resorption while stimulating bone regeneration. In this study we established a novel processing for the foaming of a polymer (poly-epsilon-caprolactone) and simultaneous chemical reaction of a mixture of calcium and strontium hydroxides to the respective carbonates using supercritical carbon dioxide. The resultant porous composite scaffold was optimized in composition and strontium content and was characterized via different spectroscopic (infrared and Raman spectroscopy, energy dispersive X-ray spectroscopy), imaging (SEM, mu CT), mechanical testing and in vitro methods (fluorescence vital staining, MTT-assay). As a result, the composite scaffold showed good in vitro biocompatibility with partly open pore structure and the expected chemistry. First mechanical testing results indicate sufficient mechanical stability to support future in vivo applications. (C) 2016 Elsevier B.V. All rights reserved.}, language = {en} } @article{ZehbeKolloscheLardongetal.2016, author = {Zehbe, Kerstin and Kollosche, Matthias and Lardong, Sebastian and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas}, title = {Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties}, series = {International journal of molecular sciences}, volume = {17}, journal = {International journal of molecular sciences}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms17030391}, pages = {16}, year = {2016}, abstract = {Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.}, language = {en} } @article{ZehbeLangeTaubert2019, author = {Zehbe, Kerstin and Lange, Alyna and Taubert, Andreas}, title = {Stereolithography Provides Access to 3D Printed lonogels with High Ionic Conductivity}, series = {Energy Fuels}, volume = {33}, journal = {Energy Fuels}, number = {12}, publisher = {American Chemical Society}, address = {Washington}, issn = {0887-0624}, doi = {10.1021/acs.energyfuels.9b03379}, pages = {12885 -- 12893}, year = {2019}, abstract = {New ionogels (IGs) were prepared by combination of a series of sulfonate-based ionic liquids (ILs), 1-methyl-3-(4-sulfobutyl)imidazolium para-toluenesulfonate [BmimSO(3)][pTS], 1-methyl-1-butylpiperidiniumsulfonate para-toluenesul-fonate [BmpipSO(3)] [pTS], and 1-methyl-3-(4-sulfobutyl) imidazolium methylsulfonate [BmimSO(3)H][MeSO3] with a commercial stereolithography photoreactive resin. The article describes both the fundamental properties of the ILs and the resulting IGs. The IGs obtained from the ILs and the resin show high ionic conductivity of up to ca. 0.7.10(-4) S/cm at room temperature and 3.4-10(-3) S/cm at 90 degrees C. Moreover, the IGs are thermally stable to about 200 degrees C and mechanically robust. Finally, and most importantly, the article demonstrates that the IGs can be molded three-dimensionally using stereolithography. This provides, for the first time, access to IGs with complex 3D shapes with potential application in battery or fuel cell technology.}, language = {en} } @article{PereiraZehbeGuenteretal.2018, author = {Pereira, Rui F. P. and Zehbe, Kerstin and G{\"u}nter, Christina and dos Santos, Tiago and Nunes, Silvia C. and Almeida Paz, Filipe A. and Silva, Maria M. and Granja, Pedro L. and Taubert, Andreas and de Zea Bermudez, Ver{\´o}nica}, title = {Ionic liquid-assisted synthesis of mesoporous silk fibroin/silica hybrids for biomedical applications}, series = {ACS Omega}, volume = {3}, journal = {ACS Omega}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {2470-1343}, doi = {10.1021/acsomega.8b02051}, pages = {10811 -- 10822}, year = {2018}, abstract = {New mesoporous silk fibroin (SF)/silica hybrids were processed via a one-pot soft and energy-efficient sol-gel chemistry and self-assembly from a silica precursor, an acidic or basic catalyst, and the ionic liquid 1-butyl-3-methylimidazolium chloride, acting as both solvent and mesoporosity-inducer. The as-prepared materials were obtained as slightly transparent-opaque, amorphous monoliths, easily transformed into powders, and stable up to ca. 300 degrees C. Structural data suggest the formation of a hexagonal mesostructure with low range order and apparent surface areas, pore volumes, and pore radii of 205-263 m(2) g(-1), 0.16-0.19 cm(3) g(-1), and 1.2-1.6 nm, respectively. In all samples, the dominating conformation of the SF chains is the beta-sheet. Cytotoxicity/bioactivity resazurin assays and fluorescence microscopy demonstrate the high viability of MC3T3 pre-osteoblasts to indirect (>= 99 +/- 9\%) and direct (78 +/- 2 to 99 +/- 13\%) contact with the SF/silica materials. Considering their properties and further improvements, these systems are promising candidates to be explored in bone tissue engineering. They also offer excellent prospects as electrolytes for solid-state electrochemical devices, in particular for fuel cells.}, language = {en} } @article{BalischewskiBehrensZehbeetal.2020, author = {Balischewski, Christian and Behrens, Karsten and Zehbe, Kerstin and G{\"u}nter, Christina and Mies, Stefan and Sperlich, Eric and Kelling, Alexandra and Taubert, Andreas}, title = {Ionic liquids with more than one metal}, series = {Chemistry - a European journal}, volume = {26}, journal = {Chemistry - a European journal}, number = {72}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.202003097}, pages = {17504 -- 17513}, year = {2020}, abstract = {Thirteen N-butylpyridinium salts, including three monometallic [C4Py](2)[MCl4], nine bimetallic [C4Py](2)[(M1-xMxCl4)-M-a-Cl-b] and one trimetallic compound [C4Py](2)[(M1-y-zMyMz (c) Cl4)-M-a-M-b] (M=Co, Cu, Mn; x=0.25, 0.50 or 0.75 and y=z=0.33), were synthesized and their structure and thermal and electrochemical properties were studied. All compounds are ionic liquids (ILs) with melting points between 69 and 93 degrees C. X-ray diffraction proves that all ILs are isostructural. The conductivity at room temperature is between 10(-4) and 10(-8) S cm(-1). Some Cu-based ILs reach conductivities of 10(-2) S cm(-1), which is, however, probably due to IL dec. This correlates with the optical bandgap measurements indicating the formation of large bandgap semiconductors. At elevated temperatures approaching the melting points, the conductivities reach up to 1.47x10(-1) S cm(-1) at 70 degrees C. The electrochemical stability windows of the ILs are between 2.5 and 3.0 V.}, language = {en} } @misc{ZehbeKolloscheLardongetal.2017, author = {Zehbe, Kerstin and Kollosche, Matthias and Lardong, Sebastian and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas}, title = {Ionogels based on poly(methyl methacrylate) and metal-containing ionic liquids}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-400607}, pages = {16}, year = {2017}, abstract = {Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.}, language = {en} } @article{AbouserieZehbeMetzneretal.2017, author = {Abouserie, Ahed and Zehbe, Kerstin and Metzner, Philipp and Kelling, Alexandra and G{\"u}nter, Christina and Schilde, Uwe and Strauch, Peter and K{\"o}rzd{\"o}rfer, Thomas and Taubert, Andreas}, title = {Alkylpyridinium Tetrahalidometallate Ionic Liquids and Ionic Liquid Crystals: Insights into the Origin of Their Phase Behavior}, series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, journal = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-1948}, doi = {10.1002/ejic.201700826}, pages = {5640 -- 5649}, year = {2017}, abstract = {Six N-alkylpyridinium salts [CnPy](2)[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C4Py](2)[MCl4] compounds are monoclinic and crystallize in the space group P2(1)/n. The crystals of the longer chain analogues [C12Py](2)[MCl4] are triclinic and crystallize in the space group P (1) over bar. Above the melting temperature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl4](2-) ions in the Cu-based ILs have a distorted tetrahedral geometry.}, language = {en} } @article{AbouserieZehbeMetzneretal.2017, author = {Abouserie, Ahed and Zehbe, Kerstin and Metzner, Philipp and Kelling, Alexandra and G{\"u}nter, Christina and Schilde, Uwe and Strauch, Peter and K{\"o}rzd{\"o}rfer, Thomas and Taubert, Andreas}, title = {Alkylpyridinium Tetrahalidometallate Ionic Liquids and Ionic Liquid Crystals: Insights into the Origin of Their Phase Behavior}, series = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, journal = {European journal of inorganic chemistry : a journal of ChemPubSoc Europe}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-1948}, doi = {10.1002/ejic.201700826}, pages = {5640 -- 5649}, year = {2017}, abstract = {Six N-alkylpyridinium salts [CnPy](2)[MCl4] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C4Py](2)[MCl4] compounds are monoclinic and crystallize in the space group P2(1)/n. The crystals of the longer chain analogues [C12Py](2)[MCl4] are triclinic and crystallize in the space group P (1) over bar. Above the melting temperature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl4](2-) ions in the Cu-based ILs have a distorted tetrahedral geometry.}, language = {en} }